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Content

INTRODUCTION 3

MODAL VERBS 7

Can 11

may 18

we can compare may and can 24

must 25

must and may compared 28

to have to 29

to be to 31

must, to have to and to be to compared 32

ought to 34

Shall and should 35

shall 35

should 36

must, should and ought to compared 41

Should + perfect infinitive, ought to + perfect infinitive and was/were to + perfect infinitive compared 41

will 42

need 47

dare 48

Shouldnt + Perfect Infinitive, oughtnt to + Perfect Infinitive and neednt + Perfect Infinitive compared 49

Final conclusion 50

BIBLIOGRAPHY 52

Introduction

Modality is expression of speakers attitude to what his utterance denotes.

The speakers judgment may be of different kinds, that is, the speaker may express various modal meanings. Modal verbs unlike other verbs, do not denote actions or states, but only show the attitude of the speaker towards the action expressed by the infinitive in combination with which they form compound modal predicates. These modal verbs may show that the action (or state, of process, or quality) is viewed by the speaker as possible, obligatory, doubtful, certain, permissible, advisable, requested, prohibited, ordered etc. Modal verbs occur only with the infinitive. This or that meaning is to a great degree determined by communicative type of the sentence and the form of the infinitive. That is a huge problem for foreign learners of English, who make a great deal of mistakes in this field. So, the aim of my work is to show how modal verbs can be used, in what case we need one or other verb and why.

English modality can be expressed not only by modal verbs. Modality can be expressed by different linguistic means. In actual speech all forms expressing modality work together to make the meaning clear. But in every case there is some leading form that expresses the main attitude. These forms fall into four categories: phonetic (intonation), grammatical (mood), lexico-grammatical (modal verbs), lexical (modal words and phrases). But the most important from them is the third form, which includes modal verbs. It is important to take into account one more feature peculiar to modal verbs. They all show that a certain action is represented as necessary, doubtful, etc. From the point of view of the speake, there are verbs which `help other verbs to express a meaning: it is important to realize that “modal verbs” have no meaning by themselves/ A modal verb such as would has several varying functions; it can be used, for example, to help verbs express ideas about the past, the present and the future. It is therefore wrong to simply believe that “would is the past of will”: it is many other things.

English modality can be expressed not only by modal verbs. There are many ways to express it - generally Mood shows the relation between the action expressed by the predicate verb and reality. The speaker establishes this relation.

In present-day English the category of mood is made up by a set of forms opposed to each other in presenting the event described as a real fact, a problematic action of as something unreal that does not exist.

Actions represented as real facts are expressed by the Indicative Mood.

E.g. Architects have done some very good work, too, in designing new schools. Many of these are prefabricated, which means that as much of the building work as possible if done not on the building site but in factories where mass production methods are used.

When the brothers had gone home, Mr. Waterfall announced that they were a much pleasanter pair of young men than the had been led to believe.

The Indicative mood is characterized by a great number of tense-aspect-phase forms that may be used in the Active or in the Passive Voice. It should be stressed that the use of the Indicative Mood does not always mean that the action expressed by the predicate verb is true to fact, that it actually takes (or took, or will take) place in reality. When the speaker uses the Indicative Mood he merely represents an action as a fact, but he maybe mistaken or even telling a lie.

E.g. “Ive seen to it,” he said, but everyone knew it was not true.

Commands and requests, which are problematic actions, are expressed by the Imperative Mood.

The Imperative Mood is the plain stem of the verb (e.g. Come over here. Listen to him, etc.). It may be used in the affirmative and in the negative form The negative form is an analytical form built up by means of the plain stem of the auxiliary verb to do followed by not (dont) and the infinitive of the notional verb without to (e.g. Dont go over there. Dont listen to him, etc.). The negative form of the verb to be is also built up by means of the auxiliary verb to do (e.g. Dont be inquisitive. Dont be a fool, etc.).

If we wish to make a command or request more expressive, we use the emphatic form. Its also an analytical form built up with the help of the plain stem of the auxiliary verb to do which is placed before the notional verb, including to be (e.g. Do come over here. Do listen to him. Do be quiet, etc.).

A command or request is generally addressed to the second person singular or plural. There is usually no need to mention the subject of the action before the verb in the Imperative mood. But occasionally the verb may be preceded by you in familiar style (e.g. You dont worry.).

A command or request may be addressed to the first person plural. It is also formed with the help of the plain stem of the verb, to let followed by the pronoun us (the contracted form is lets) and the infinitive of the notional verb. This form is actually an invitation to a joint action (e.g. Lets have a cup of tea. Lets do it together, etc.).

Actions represented as unreal are in present-day English express by a variety of forms.

Among them there is a mood form - the conditional Mood.

The fact that there are a number of forms engaged in expressing unreal actions could be explained historically.

In the older periods English used to be a synthetic language and had special forms that served to express unreal actions - the so-called Subjunctive mood. It was built up synthetically by means of inflections. As a result of loss of inflections, the difference between the forms of the Indicative Mood and the Subjunctive Mood has in most cases disappeared. The place of the old Subjunctive Mood was in a number of cases taken up by analytical forms and modal phrases, i.e. combinations of modal verbs with the infinitive. It is this historical process that accounts for the great variety of different forms expressing unreality in modern English.

As some of the forms expressing problematic or unreal actions are modal phrases, it is necessary before describing the different forms of unreality to treat modal verbs first.

The speakers attitude towards the action if the sentence may be expressed in different ways:

By one of the mood forms that serve to show whether the action is represented as a real fact of as problematic, or unreal, this form of expression is found in every sentence because it is indispensable to predication.

By modal verbs which represent an action as necessary or unnecessary, possible or impossible, certain of doubtful and the like. But modal verbs need not be used in every sentence and are, therefore, to be regarded as an additional means of expressing the speakers attitude towards the action in the sentence.

By attitudinal adverbs such as certainly, perhaps, probably, luckily, unfortunately, etc. They express different degrees of certainty on the part of the speaker of the desirability of the action from his point of view.

Modal Verbs

We find the following modal verbs in English: can, may, must, ought, shall, should, will, need and dare. Besides, to have and to be in some of their uses are also classed among modal verbs. A modal verb in combination with the infinitive forms a modal compound predicate.

Modal verbs are defective verbs since they lack many forms characteristic of regular verbs: they have no -s in the third person singular in the present tense and no verbal, so they have no analytical forms; some of them lack the form of the past tense.

Modal verbs have the following peculiarities:

they are followed by the infinitive without the particle to (with the exception of ought, to have and to be);

their interrogative and negative forms are built up without the auxiliary do.

Most of the verbs have more than one meaning. Each of their meanings is characterized by a specific usage.

Some of the meanings may be found in all kinds of sentences; others occur only in affirmative of interrogative or negative sentences;

Different meanings may be associated with different forms of the infinitive - simple and perfect (both in the active and passive forms), continuous and perfect continuous;

If the modal verbs have more than one form (can - could, may - might, will - would, also the verbs to have and to be), their different meanings are not necessarily found in all those forms.

The use of modal verbs is in most cases independent of the structure of the sentence: the use of this of that modal verb is determined by the attitude of the speaker towards the facts contained in the sentence. In this case we may speak of the free or independent use of modal verbs.

E. g. He admires you. He thinks youre a little beauty. Perhaps I oughtnt to have told you that.

He may be in the hall now, waiting for me.

But sometimes the use of certain modal verbs depends on the structure of the sentence, mainly on the type of the subordinate clause, and occasionally also on the lexical character of the predicate verb in the principal clause. This may be called the structurally dependent use of modal verbs.

E. g. It is obviously necessary that an investigation should be made.

Christine feared she might not be met at all.

When the use of modal verbs is structurally dependent, their meaning is sometimes weakened; in fact, it may be quite vague. This may be accounted for by the fact that these verbs become rather part of the structure than bearers of individual meaning.

It is important to take into account one more feature peculiar to modal verbs. They all show that a certain action is represented as necessary, possible, desirable, doubtful, etc. from the point of view of the speaker. Consequently, modal verbs are generally used in conversation. In past-time contexts they may be found only in reported speech or thought, Thus You should have done it before, or He might be wrong, or It must be true cannot be possibly found in narration unless they are used after He thought that … He said that … He knew that …, etc.

The only exceptions are the past tense forms could, would, had, was and might which may be used only in conversation but also in narration.

E. g. Walker was illiterate and could not sign his name.

When I looked at her I saw tears in her eyes. So I had to tell her the truth.

We cant but mention that modal verbs are of common usage in literature - both American and English. In this work several examples taken from the works of famous American and English writers of the 18-19^th centuries, such as I. Asimov, O. Henry, S. Maugham, F. Scott Fitzgerald, A. Christie, O. Wilde, M. Spark and others, can vividly show you their usage and importance in speech. We guess itll be necessary to provide you with some examples on their usage from different newspapers and analyze them thoroughly.

Can

The modal verb can has the following forms: can - the present tense (e.g. He can speak English) and could - the past tense. The form could is used in two ways: a) in past-time contexts as a form of the Indicative Mood (e.g. He could speak English when he was a child), b) in present-time contexts to express unreality, or as a milder and more polite form of can, or as a form implying more uncertainty than can (e.g. He could speak English if necessary. Could I help you? Could it be true?). Compare with the Russian мог бы: Он мог бы сделать это, если бы у него было время (unreality). Не мог бы я Вам помочь? (politeness). Неужели он мог бы так сказать? (uncertainty).

Can has the following meanings:

ability, capability,

E.g. I can imagine how angry he is.

We can represent a figure of a three-dimensional solid.

This meaning may also be expressed by to be able . The phrase can be used in all tense-forms if necessary.

In the meaning of ability and capability can occurs in all kinds of sentences.

E.g. Right and left we can go, backward and forward freely enough, and men always have done so. You can move about in all directions of Space, but you cannot move about in Time.

In this case can is followed by the simple infinitive and reference is made to the present. But depending on the context it may also refer to the future.

E.g. He can go up against gravitation in a balloon, and why should he not hope that ultimately he may be able to stop or accelerate his drift along the Time-Dimension, or even turn about and travel the other way?

However, if the time reference is not clear from the context or if it is necessary to stress that the action refers to the future, shall/will be able is used.

E.g. He will be able to write to us from Portugal. I shall be able to earn by own living soon.

The form could may be used in past-time contexts and in this case it is followed by a simple infinitive. It is a form of the Indicative Mood here.

E.g. A man could not cover himself with dust by rolling in a paradox, could he? But then where could it be? After what had happened I couldnt trust him.

The form could may also be used in present-time context in combination with the simple infinitive to express unreality with reference to the present or future.

E.g. I told myself that I could never stop, and with a gust of petulance I resolved to stop forthwith. (не смог бы прекратить).

You could articulate more distinctly with that cigarette our of your mouth. (мог бы говорить более отчетливо).

As the form could may be used in two ways it is usually undertoosd as expressing unreality with reference to the present or future unless there are indications of past time in the sentence or in the context. Thus the sentence She could paint landscapes will be understood as Она могла бы писать пейзажи.

If there is no indication of past time in the context but the speaker wishes to refer the action to the past, was/were able is used of could to avoid ambiguity.

E.g. She was able to explain the mystery.

In combination with the perfect infinitive could indicates that the action was not carried out in the past.

E.g. She could have explained the mystery. (Она могла бы объяснить эту тайну; но не объяснила).

possibility due to circumstances.

E.g. You can see the forest through the other window.

We can use either the Present Perfect of the Present Perfect Continuous in this sentence.

In this meaning can is found in all kinds of sentences. It is followed by the simple infinitive and it refers the action to the present of future.

E.g. You can obtain a dog from the Dogs Home.

Can we use the indefinite article with this noun?

We cant use the indefinite article with this noun.

In past-time contexts the form could is used. It is followed by the simple infinitive in this case.

E.g. You could see the forest through the other window before the new block of houses was erected.

The form could in combination with the simple infinitive may also express unreality with reference to the present of future.

E.g. You could see the houses from here if it were not so dark.

In combination with the perfect infinitive, could indicate that the action was not carried out in the past.

E.g. You could have seen the house from there if it had not been so dark.

Permission

E.g. You can take my umbrella.

Can in this meaning is found in affirmative sentences, interrogative sentences in which a request is expressed, and in negative sentences where it expresses prohibition.

E.g. You can use my car. Can I use your car? You cant use my car today.

In this meaning can is combined with the simple infinitive.

The form could with reference to the present is found only in interrogative sentences in which it expresses a more polite request.

E.g. Could I use your car?

The form could is found in reported speech (i.e. in accordance with the rules of the sequence of tenses).

E.g. He said that I could use his car.

He asked me if he could use my car.

uncertainty, doubt

E.g. Can it be true?

In this meaning can is found only in interrogative sentences (in general questions). Besides, sentences of this kind are often emotionally colored and so their application is rather restricted.

Depending on the time reference, can in this meaning is used in combination with different forms of the infinitive.

Thus, if reference is made to the present, the simple infinitive is found with static verbs.

E.g. Can he really be ill?

Can it be so late?

With dynamic verbs, the continuous infinitive is used.

E.g. Can she be telling lies?

Can he be making the investigation all alone?

Can in combination with the perfect infinitive refers the action to the past.

E.g. Can he have said it? Can she have told a lie?

The combination of can with the perfect infinitive may also indicate an action begun in the past and continued into the moment of speaking. This is usually found with static verbs.

E.g. Can she really have been at home all this time?

However, if can is followed by a dynamic verb the Perfect Continuous infinitive is used.

E.g. Can she have been waiting for us so long?

Could with reference to the present is also used in this way, implying more uncertainty.

E.g. Could it be true?

Could she be telling lies?

Could he have said if?

Could she have been waiting for us so long?

In Russian both variants, with can and could, are rendered in the same way: Неужели это правда? Неужели он лжет? And so on.

Improbability

E.g. It cant be true. (Это не может быть правдой. Вряд ли это так.)

In this meaning can is found only in negative sentences, which are often emotionally colored. Depending on the time reference, this can is also used with different forms of the infinitive/

E.g. He cant be really ill.

She cant be telling lies.

He cant have said it.

She cant have been at home all this time.

She cant have been waiting for us so long.

Could is also used in this way making the statement less categorical

E.g. It couldnt be true.

She couldnt be telling lies.

He couldnt have said it.

She couldnt have been at home all this time.

She couldnt have been waiting for us so long.

Can and could followed by different forms of the infinitive, are found in special questions where they are used for emotional coloring (to express puzzlement, impatience, etc.).

E.g. What can (could) he mean?

What can (could) he be doing?

What can (could) he have done?

Where can (could) he have gone to?

It can be rendered in Russian as: Что, собственно, он имеет в виду?

As is seen from the above examples, the form could referring to present is sometimes clearly opposed to can in that it expresses unreality whereas can expresses reality. This may be observed in the following meanings:

ability - He can speak English. He could speak English if necessary.

possibility due to circumstances - You can get the book from the library. You could get the book from the library if necessary. E.g. “You can have a million books on our television screen, and even more. There is nothing to throw away.” (I. Asimov)

“How could a man be a teacher? “ (I. Asimov)

In the other meanings, however, this difference between the two forms is obliterated. Could is used either as a milder or mote polite form of can as a form implying more uncertainty than can:

permission - Can I use your pen? Could I use your pen? (more polite)

uncertainty, doubt, improbability - Can it be true? Could it be true (less certain). It cant be true. It couldnt be true (less certain).

We can also find some examples of modal verbs usage in some newspapers , magazines or in literature.

E.g. It could be true but it is advisable to find out first what has really happened there. (Может быть, это и правда, но лучше сначала выяснить, что же действительно там произошло.)

“Honey, you couldnt support a wife,” she answered cheerfully. “Anyway, I know you too well to fall in love with you.” (F. Scott Fitzgerald)

In this case the verb could is used here in the meaning of doubt, uncertainty and improbability.

May

The modal verb may has the following forms: may - the Present tense (e.g. it may be true) and might - the Past tense. The form might is used in two ways: a) in past-time contexts, mainly in reported speech in accordance with the rules of the sequence of tenses (e.g. He told me that it might be true) and b) in present-time contexts as a milder and more polite form of may, or as a form implying more uncertainty than may (e.g. Might I come and see you? It might be true), or to express unreality (e.g. He might have fallen ill if he hadnt taken the pills).

May has the following meanings:

1) supposition implying uncertainty

E.g. He may be busy getting ready for his trip.

In Russian this meaning is generally rendered by means of the modal adverbs возможно and может быть.

In English this meaning may also be rendered by means of the attitudinal adverbs perhaps and maybe.

In the meaning of supposition implying uncertainty the verb may occurs in affirmative and negative sentences.

E.g. He may be at home.

He may not be at home (Возможно, что его нет дома).

Two factors may temporarily have increased their caution. (W. Faulkner)

In this meaning may can be followed by different forms of the infinitive depending on the time reference expressed.

May in combination with the simple infinitive usually refers the action to the future.

E.g. He may come soon.

The action may also refer to the present but only with stative verbs.

E.g. He may be ill.

He may not know about it.

May in combination with the Continuous infinitive of dynamic verbs refers the action to the present.

E.g. Its too late to phone him now. He may be sleeping.

I never see him about now. For all I know, he may be writing a book.

May in combination with the Perfect infinitive refers the action to the past.

E.g. He may have fallen ill.

“Whats happened to the dog?” I asked. “It isnt here. His master may have taken it with him.”

The combination of may with the Perfect infinitive may also indicate an action begun in the past and continued into the moment of speaking. This is usually found with stative verbs.

E.g. He may have been at home from about two hours.

However, if may is followed by a dynamic verb, the Perfect Continuous infinitive is used.

E.g. He may have been waiting for us for an hour.

In the meaning of supposition implying uncertainty, the form might is also found. It differs from the form may in that it emphasizes the idea of uncertainty. It may be followed by the simple, Continuous or Perfect infinitive.

E.g. He might come soon. He might be ill.

He might be doing his lesson now. He might have spoken to her yesterday.

possibility due to circumstances

E.g. You may order a taxi by telephone.

A useful rough-and-ready rule is that rime adverbs may come at either end of the sentence, but not in the middle.

May in this meaning occurs only in affirmative sentences and is followed only by the simple infinitive.

The form might is used in past-time contexts in accordance with the rules of the sequence of the tenses.

E.g. He said the might order a taxi by telephone.

Might followed by the Perfect Infinitive indicates that the action was not carried out owning to certain circumstances (expressed in the sentence or implied).

E.g. He might have fallen ill if he hadnt taken the medicine.

Luckily he wasnt driving the car. He might have been hurt.

You are so careless. You might have broken the cup. (Ты чуть было не разбил чашку).

It seemed to him that the most interesting thing in life was what might lie just around the corner. (O. Henry)

permission

E.g. The director is alone now. So you may see him now.

If you have got a car and can drive, you may spend part of your holiday moving from place to place. (C. Eckersley)

May in this meaning is found in affirmative sentences, in interrogative sentences which usually express a request, and in negative sentences where it denotes prohibition. But in negative sentences it is not common as prohibition is generally expressed by other modal verbs (see can and must).

E.g. You may smoke in here. May I smoke in here? You may not smoke in here.

In this meaning may is combined only with the simple infinitive. In interrogative sentences the form might is also found when we wish to express a more polite request.

E.g. May I join you?

In reported speech the form might is used.

E.g. He told me that I might smoke in the room He asked me if he might join us.

disapproval or reproach

E.g. You might carry the parcel for me. You might have helped me.

Here we find only the form might used in affirmative sentences and followed by the simple of Perfect infinitive. In the latter case it expressed reproach for the nonperformance of an action.

The form might which expresses unreality is not always parallel to may. Might expresses unreality only in combination with the Perfect infinitive.

E.g. You might have let me know about it beforehand.

There was a car accident in front of our house. Luckily Tommy was at school. He might have been killed.

In most cases might is used as a milder and more polite form than may of as a form implying a greater degree of uncertainty:

permission - May I call to my mother now? Might I call to my mother now? (very polite)

Might I take the liberty of pointing out that you have made a small mistake? (J. Joyce)

supposition - He may come a little later. He might come a little later (less certain).

The Chancellors measures might help towards an agreement on an incomes policy. (Moscow News).

The two forms are not opposed in the meaning of possibility due to circumstances where only may is used, nor in the meaning of disapproval of reproach where might alone is found.

E.g. You may find the book at the library.

You might have considered your parents feelings.

May as well (might as well, might just as well) + infinitive is a very mild and an emphatic way of expressing an intention. It is also used to suggest of recommend an action.

E.g. I may as well take the child with me. (Я, пожалуй, возьму ребенка с собой. Пожалуй, будет лучше, если я возьму ребенка с собой).

You may as well give him the letter. I might as well stay at home tonight.

“Ill go at six.” “Thats far too late; you might just as well not go at all.” (Можно было бы и не ходить туда совсем).

It might have been worse means “Things are not so bad after all.” In Russian it is rendered as: Могло бы быть и хуже or в конце концов дела обстоят не так уж и плохо).

He might have been a … means `He might have been taken for a … `He looked as a …

E.g. Roy Wilson, the new doctor, was twenty-eight, large, heavy, mature and blond. He might have been a Scandinavian sailor.

If I may say so … has become a stereotyped phrase in which the meaning of permission is considerably weakened.

E.g. If I may say so, I think you have treated him very badly.

In addition to the above cases illustrating the independent use of may, this modal verb occurs in subordinate object clauses after expressions of fear as well as in adverbial clauses of purpose and concession.

Here are some more examples from the works of the English and American literature:

E.g. Try as she might, her poor head just wouldnt let her think what it was she should rightly remember.(O. Wilde)

You certainly wont. You may freeze your nose, but you wont be shivery cold. Its hard and dry, you know. (F. Scott Fitzgerald)

We can compare May and Can

The use of can and may is parallel only in two meanings: possibility due to circumstances and permission. In these meanings, however, they are not always interchangeable for a number of various reasons.

Thus in the meaning of possibility due to circumstances the use of may is restricted only to affirmative sentences, whereas can is found in all kinds of sentences.

Can - He can find this book at the library. Can he find this book at the library? He cannot find this book at the library.

May - He may find this book at the library.

Their time reference is also different. May refers only to the present or future: the form might is used in past-time contexts only in reported speech. Can (could) may refer to the present, pastor future.

May - He may find the book at the library. I said that he might find the book at the library.

Can - He can find the book at the library. He could find the book at the library yesterday. He can find the book at the library tomorrow.

Both could and might combined with the Perfect infinitive indicate that the action was not carried out in the past.

E.g. He might have found the book at the library.

He could have found the book at the library.

It follows from the above that the sphere of application of can in this meaning is wider than that of may.

When may and can express permission the difference between them is rather that of style than of meaning - may is more formal than can which is characteristic of colloquial English.

E.g. May (might) I speak to you for a moment, professor?

Can (could) I have a cup of tea, mother?

May in negative sentences expressing prohibition is uncommon.

Must

The modal verb must has only one form it is used in present-time contexts with reference to the present of future and in combination with the Perfect infinitive it refers to the past. In past-time contexts this form is used only in reported speech, i.g. the rules of the sequence of tenses are not observed with must.

Must has the following meanings:

obligation (from the speakers point of view)

E.g. Any real body must have extension in four directions: it must have Length, Breadth, Thickness, and - Duration.

In different contexts must may acquire additional shades of meaning, such as duty or necessity.

In this meaning must is found in affirmative and interrogative sentences and followed only by the simple infinitive.

Prohibition

E.g. He must not leave his room for a while. (Он не должен (ему нельзя) выходить из комнаты некоторое время).

This meaning is expressed in negative sentences and must is also followed by the simple infinitive.

emphatic advice

E.g. You must come and see us when youre in London.

You must stop worrying about your son.

You mustnt give another thought to what he said.

You mustnt miss the film. It is very interesting.

You must have your hair cut.

It is much too long. You mustnt cry.

“Andy” - she spoke in a quick, low voice - “of course you must never tell anybody what I told you about Canby yesterday.” (F. Scott Fitzgerald)

This meaning is found in affirmative and negative sentences and is closely connected with the two above mentioned meanings.

supposition implying strong probability

E.g. Watson, we must look upon you as a man of letters.

It must be late as the streets are deserted.

Must in this meaning is found only in affirmative sentences. In Russian this meaning is generally rendered by means of the attitudinal adverbs вероятно, должно быть.

In English this meaning may also be expressed by means of the attitudinal adverb probably.

In this meaning must may be followed by different forms of the infinitive. If reference is made to the present, the Continuous infinitive is used with dynamic verbs.

E.g. The book is not on the shelf. Jane must be reading it. Lets have something to eat. You must be starving.

If must is followed by the simple infinitive of dynamic verbs, it expresses obligation.

E.g. Jane must read the book. You must stay here.

However, with stative verbs the simple infinitive is used to express supposition.

E.g. He must be over fifty.

He must know all about it as he has read a lot on the subject.

“He must be a Southerner, judging by those trousers,” suggested Harry mischievously. (F. Scott Fitzgerald)

Must in combination with the Perfect Infinitive refers the action to the past.

E.g. You must have examined the house very carefully, to find a single pellet of paper.

It must have been his first taste of peace for years.(A. Marshall)

The combination of must with the Perfect Continuous infinitive indicates an action begun in the past and continued into the moment of speaking.

E.g. It must have been raining all the night. There are big puddles in the garden.

However, if must is followed by a stative verb, the Perfect infinitive is used.

E.g. He must have been here since breakfast. He must have known it all along.

When must expresses supposition implying strong probability, its use is restricted in two ways:

It is not used with reference to the future. In this case we find attitudinal adverbs in the sentence.

E.g. She must really love you to distraction. He must evidently know all about it

It is not used in the interrogative or negative forms. It is found only in the affirmative form.

Must needs denotes obligation.

E.g. He must needs go there. (Он непременно должен пойти туда.)

“I think you must ask somebody else to your party instead of Henry, Jim” (B. J. Chute)

“Yes, but I must wash before dinner,” Jimmy said and added, “Youre lucky. Dirt doesnt show on you.” (B.J. Chute)

I must be going and I must be off both mean - it is time for me to go (in Russian - мне пора уходить).

I must tell you that … and I must say … are stereotyped phrases in which the meaning of obligation is considerably weakened in must.

In the sentences: You must come and see me some time You must come and have a dinner with me. You must come to our party. You must come and stay with us for the weekend and the like, the meaning of obligation in must is also weakened. Must has become part of such sentences which are a common way of expressing invitations.

Must and May compared

Must and may can be compared in two meanings:

Both may and must serve to express supposition but their use is not parallel. May denotes supposition implying uncertainty whereas the supposition expressed by must implies strong probability

E.g. For all I know, he may be an actor. His face seems so familiar. He must be an actor. His voice carries so well. I saw him an hour ago. He may still be in his office now. He always comes at 10 sharp. So he must be in his office now.

They must be satisfied with going to the piers… (M. Spark)

May and must are used to express prohibition in negative sentences. But may is seldom found in this meaning. In negative answers to questions with may asking for permission we generally find must not or cannot.

E.g. `May I smoke here?” “No, you mustnt (you cant).

To have to

To have to as a modal verb is not a defective verb and can have all the necessary finite forms as well as the verbal.

E.g. He is an invalid and has to have a nurse.

She knew what she had to do.

He frightened her - I had to yield him my last date before Bill came. (F. Scott Fitzgerald0

I shall have to reconsider my position.

He is always having to exercise judgment.

My impression was that he was having to force himself to talk.

I have had to remind you of writing to her all this time.

The women at barfed had had to be told that an experiment was taking place that day. “As a matter of fact,” he said, “Ive been having to spend some time with the research people.”

It wouldnt have been very nice for the Davids sons to have to mix with all those people in the smoking-room.

Having to work alone, he wanted all his time for his research.

The interrogative and negative forms of the modal verb to have to are built up by means of the auxiliary verb to do.

E.g. Why do I have to do everything?

Did he have to tell them abo ...........